Endoscopic Prelacrimal Approach and Modified Endoscopic Denker’s Approach to the Middle Cranial Fossa

Introduction: Tumors within the middle cranial fossa demand intricate surgical approaches, including lateral craniotomy and the endoscopic endonasal approach (EEA). EEA offers benefits such as minimal invasiveness, reduced brain manipulation, and decreased retraction. In specific cases, combining EEA with extended approaches can expand the surgical exposure area and reduce associated risks.

Patient: A 55-year-old woman presented with right facial sensations of electric-like tingling, numbness, and paresthesia persisting for eight years but worsening recently. Brain MRI with and without contrast enhancement revealed a 4.8-cm lesion involving the right pterygopalatine fossa, infratemporal fossa, middle cranial fossa, and posterior cranial fossa. We performed an EEA with medial maxillectomy, combining the prelacrimal approach and the modified endoscopic Denker’s approach, achieving gross total tumor removal. The pathological report confirmed the presence of a schwannoma. Postoperative brain MRI showed no significant residual tumor. Her recovery has been quite satisfactory, with only minimal numbness and paresthesia remaining in the right V2 territory.

Discussion: Trigeminal schwannoma, the second most common intracranial schwannoma after vestibular schwannoma, poses complex surgical challenges due to potential extensions. Several factors, including exposure, visualization, brain retraction, freedom for endoscope and instrument manipulation, and reconstruction methods need to be carefully considered. The primary goal is gross total resection.

EEA with a transpterygoid approach and medial maxillectomy provides middle cranial fossa access, though visualization is limited due to obstructing bony structures and neurovascular elements.

The prelacrimal approach is specifically designed for maxillary sinus, pterygopalatine fossa, and infratemporal fossa lesions, offering a broader exposure range, improved attack angles, and preservation of nasal structures, including the nasolacrimal duct. Introducing three or four instruments through the bony window remains challenging.

The modified endoscopic Denker’s approach provides an additional instrument port without a sublabial incision. Preservation of the pyriform aperture prevents postoperative alar collapse and retraction.

Conclusions: Tumors affecting the pterygopalatine fossa, infratemporal fossa, middle cranial fossa, and posterior cranial fossa challenge skull base surgeons. Utilizing the EEA with medial maxillectomy, the prelacrimal approach, and the modified endoscopic Denker’s approach can yield favorable surgical outcomes with minimal complications. A multidisciplinary skull base team familiar with the intricate anatomy of these regions is paramount when managing lesions in these areas ([Figs. 1]–[4]).

Fig. 1

The preoperative MRI revealed an expansile lesion extending into the right pterygopalatine fossa, infratemporal fossa, middle cranial fossa, and posterior cranial fossa. (Red arrow: tumor in the right pterygopalatine fossa and infratemporal fossa; yellow arrow: tumor in the right middle cranial fossa; green arrow: tumor in the right posterior cranial fossa.)

Fig. 2

Two bony windows created by the prelacrimal approach and the modified endoscopic Denker’s approach.

Fig. 3

During the final stage of tumor removal, we exposed the right middle cranial fossa dura, the lateral wall of the cavernous sinus, and the porus trigeminus.

Fig. 4

The postoperative MRI revealed no significant residual tumor, and the left nasoseptal flap reconstruction appeared to be successful. (Red arrow: reconstruction by left nasoseptal flap; yellow arrow: no significant residual tumor.)

Publication History

Article published online:
05 February 2024